Menstrual Cycle while breastfeeding?

My son is almost 1 year old and I've been breastfeeding him since he was born. I had surgery yesterday for a hernia and the nurses kept asking when my last period was. Besides my postpartum bleeding, my last real cycle was right before he was conceived (July 2010). I got a lot of concerned looks and comments, but I thought it was fairly normal to not have a period while breastfeeding? I'm also on Nora-be Tab (progesterone birth control pill), which I thought was part of what's keeping me from having a period. Should I be concerned or just not let their comments get to me? Any input would be appreciated :). Thanks!

Ok, thanks, grateful301. I thought it was fairly normal, but they made me feel like something was very wrong. My milk supply is dropping and he's not nursing quite as much, so I'm assuming it'll be coming soon. For the time being, I'm enjoying not having one :).

Yeah, I wasn't worried about it at all until they started grilling me about it. We're planning on TTC in the next 6 months or so anyway, so hopefully I can get away with not having one for a little while longer :).